Predicting Recall Probability to Adaptively Prioritize Study

TL;DR

This paper introduces two models for predicting recall probability to optimize study schedules, demonstrating that the Recurrent Power Law model outperforms logistic regression in accuracy and flexibility across large datasets.

Contribution

The paper develops and compares two item-specific recall prediction models, highlighting the superior performance of the Recurrent Power Law approach for adaptive study strategies.

Findings

Recurrent Power Law model outperforms logistic regression in recall prediction

RPL model is more accurate and flexible across large datasets

Models can adapt to diverse demographics, subjects, and schedules

Abstract

Students have a limited time to study and are typically ineffective at allocating study time. Machine-directed study strategies that identify which items need reinforcement and dictate the spacing of repetition have been shown to help students optimize mastery (Mozer & Lindsey 2017). The large volume of research on this matter is typically conducted in constructed experimental settings with fixed instruction, content, and scheduling; in contrast, we aim to develop methods that can address any demographic, subject matter, or study schedule. We show two methods that model item-specific recall probability for use in a discrepancy-reduction instruction strategy. The first model predicts item recall probability using a multiple logistic regression (MLR) model based on previous answer correctness and temporal spacing of study. Prompted by literature suggesting that forgetting is better modeled by the power law than an exponential decay (Wickelgren 1974), we compare the MLR approach with a Recurrent Power Law (RPL) model which adaptively fits a forgetting curve. We then discuss the performance of these models against study datasets comprised of millions of answers and show that the RPL approach is more accurate and flexible than the MLR model. Finally, we give an overview of promising future approaches to knowledge modeling.